This invention relates generally to the application of a heating or cooling agent to limbs, arms and other body members for therapeutic purposes, and in particular to a stretchable textile heat-exchange jacket which is adapted to wrap about and conform to a body member, the jacket incorporating an array of flexible pipes through which a cold or hot fluid is circulated to cool or heat the body member at a controlled temperature level appropriate to the condition of the member.
Since ancient times, medical practitioners have known that the application of heat to the body is useful in the relief of muscle soreness and various aches and pains, as well as in the treatment of certain abnormalities. The use of heat in the treatment of arthritis and other abnormal conditions is commonplace. Heat is also employed medically in the resolution of infected areas. Also of therapeutic value in the treatment of particular conditions is the application of cold to an injured body member.
A typical thermal pack makes use of an absorbent blanket wrung out of cold or hot water, the moist blanket being then covered with a dry blanket before being wrapped about the patient's body. Such packs have limited utility, for the pack can only remain in a cold or hot state for a relatively brief period.
Another technique for creating a cold pack is to place ice cubes in a plastic bag and wrap the bag in a towel which is then applied to the site to be cooled. It has been reported in Medical World News (Aug. 3, 1981) that wrapping an arthritic knee in icepacks of this type several times a day constitutes a simple and effective way of managing pain in patients who have not been relieved by drugs. But, here again, since the ice in the pack melts, the pack has a limited effective life. Also, with a pack whose core is a cluster of ice cubes, the pack cannot be fully conformed to the member to be cooled; hence the cooling effect is uneven.
In some instances, as with athletic injuries, the prescribed treatment calls for alternative periods of heating and cooling, particularly for strained muscles, ligaments or sprains. Different types of injuries must be treated in ways appropriate to the injury. Thus joint injuries may benefit more from prolonged cold treatment, whereas muscle tears and capillary damage are best treated initially with a cold pack followed by elevated heat. Existing thermal treatment devices are either for hot or cold applications, and the same device cannot readily be switched from the one state to another. Thus one can fill a rubber bag with hot water to provide a heat pack; but if the bag is to be used for a cold application, one must replace the liquid.
Following knee, leg or other surgery on an extremity, there is usually swelling in the vicinity of the incision. When the wound is dressed in a surgical bandage, it becomes difficult to apply ice to the site to reduce swelling and promote healing. Moreover, since surgical bandages, casts and rubberized braces used during rehabilitation are relatively impermeable to perspiration and act as thermal barriers, there is often a build-up of moisture and heat under a surgical dressing. This may create a climate conducive to bacteria. Such bacterial activity may cause infection and retard the healing process. Another problem that is not relieved by conventional cold packs applied to the exterior of a cast or brace is the itching which often accompanies the healing process.
As noted in The New York Times of Apr. 14, 1981 (section C 2) in an article on modern approaches to cancer treatment, the application of heat to a body in a region containing a malignant tumor may cause this tumor to shrink and disappear. The effectiveness of heat therapy is based on the fact that cancerous tumors have poor circulation and a reduced ability to dissipate heat. "Thus a temperature of more than 113 degrees Fahrenheit would destroy cancer cells while sparing normal tissue." Yet existing heat packs or applicators are ill adapted to apply heat to a confined region at a predetermined temperature for a controllable period.
Heat is also of value when used in conjunction with chemotherapeutic agents delivered to the bloodstream during cancer treatment, for these agents may be administered more effectively if the tissues are heated and the blood vessels dilated in the region of concern. Here again, the need exists for a heat applicator capable of uniformly applying heat at a controlled temperature to a limited area of the body.